you are the first one to make more sense out of the matter...assuming the clear is as thick as you claim.
Is there reference material to back up the claims as well as it a standard measure of ALL manufactures?
On higher end foreign vehicles I find they do clear under the hood.
Most American vehicles do not clear under the hood and a lot of mainstream foreign vehicles do not clear under the hood.
I do find total paint thickness on foreign vehicles to be around 90-105 microns and America vehicle's to be 100-125 microns with both measuring similar under the hood but foreign under hood being a bit thinner but also looks like it lays down better.
So on a foreign vehicle if under hood is 35 microns and total paint thickness being 90 microns that's so 60 microns of estimate clear and considered healthy.
Door jams are also another place to measure with limited clear being sprayed here and I usually find it to be about 20 microns more than under the hood.
So what I do is measure under the hood (40 microns)
Door jams (60 microns)
Total paint (100 microns)
Then I take the under hood measurements and add to jam measurements and divide by 2.
40 + 60=100 ÷2 = 50 microns
Than I take my total paint measurements and subtract 50 microns (bare minimum bottom with primer, base and clear)
100 - 50 = 50 microns of clear
That was a bit of rambling post there but hope it kinda answers your question.